I'm going to give this a shot with as little assumptive leaps about each groups' beliefs as possible:
Atheism: The rejection of belief in any divine or supernatural entities. In the current vernacular, this relates especially to deities that have a personal relationship with followers of these divine entity or entities--the very crux of theism. Atheists, it should be noted, do not deny the possibility of god or primal source. However, not only is there zero evidence to support such a claim, there is overwhelming scientific evidence to reject it. The primal source claim, for example, leads to various ontological issues whereby logic breaks down and faith inevitably takes over (who created the creator? Etc.). Atheists see no reason to fill these empty holes with steadfast belief grounded in assumption. For this reason, they reject belief in god until good evidence is presented.
Agnosticism: This is simply not claiming to know whether a deity or deities exist. An Agnostic can still be a believer in a deity, but would only admit that such a belief is unprovable. An agnostic can also be an atheist, which would look similar to the definition for atheism with the exception of the Agnostic CHOSING to not believe based on whatever reasons he or she has for said disbelief. The atheist, by contrast, CANNOT believe god exists because of the lack of evidence--the scientific method makes it necessary to reject god like any other untestable fantastic claims. Atheist=bound to the evidence. Agnostic=more willing to take a leap of faith and willing to excuse lack of evidence due to (fill in the blank).
Deism: Belief in a divine creator, but either hard skepticism or outright disbelief that this creator has or ever had any interaction with our world by way of miracles or supernatural events. See the Jefferson Bible, or Spinoza's work.
Jannier I do take umbridge with you. How very Asian of you! The concept that we are all figments of God's imagination is in Taoism, Buddism and other Asian philosophies. Carl Jung wrote often of our connectedness in the "Collective Unconscious". Christianity differs in that it sees each soul as unique and different but important to the whole. We are not swallowed up into the great ocean like a drop of water but we are added like a cell to the honeycomb, retaining all the specialness that is the individual, intack and conscious of it's place in the afterlife. (Heaven if you like)
The truth is actually so simple and easy to understand:
In the beginning we were all one sharing one consciousness and one mind. Imagine that we were one big bucket of water. As one we decided to multiply our experiences because we had limited experiences as one being with one mind and one consciousness. We then exploded into a billion different pieces (or droplets of water) all with it's own mind, consciousness, thoughts and personalities. Our goal is now to experience as much as possible because when all of this end and our little droplets of water get added to the bucket of water we will again share one consciousness and one mind. (When your droplet of water gets added to the bucket of water you will become the bucket of water!) But we will also share in all the different experiences that all of us as individuals have experienced.
To simplify it... imagine that you and I merge into one soul (one drop). We wont be 2 minds sharing one consciousness. We will become one mind, one consciousness and one thought. You will think that you are the one and I will feel like I am the one because our energies merged together to make one. You will inherit all my experiences and I will inherit all yours. I will become you and you will become me. We will be one!
Now imagine this happening on a large scale...
Every single living/conscious being (Even Satan) will merge into one... all sharing in one collective consciousness. If you can understand this you will then also understand that we cannot judge anything as good or bad because it's all you... Loving other living beings is loving yourself!
When you really understand the above life as you know it will change. You will realize that you are not here searching for anything... you are here to experience as much as possible... Just enjoy the ride....
"As the wave is part of the sea
and the sea is all of the wave
So I am part of God
And God is all of me…"
Answer: You are God that manifested yourself to experience yourself!